On Sun, 12 Nov 2006, Dave Cullen wrote:
> The CSM has a troubleshooting chart that's pretty extensive. It says to
> rapidly move the temp lever back & forth and you should be able to hear the
> door hit the stops at both extremes. Hot inlet and warm outlet hoses means
> clogged heater core. Both hoses warm, check the vacuum at the "water valve"
> on the manifold (AC cars).
If the core was clogged, wouldn't the outlet hose be cold? Otherwise, how
is warm water getting out?
> Air flow to the vents is controlled by vacuum actuated diaphram thingies.
> The little black vacuum tank that Mark mentioned was a problem on my 78. The
> hose that feeds it is only like 1/8" and they get brittle and break. With no
> vacuum the vents won't switch. Not sure if the 77 is the same or not.
That's true on A/C cars. On non A/C cars the temperature door is
controlled by a cable. It's pretty easy to check the heater door
operastion on the non A/C cars by sticking your head under the dash on the
passenger side and working the lever.
Greg Beaulieu [EMAIL PROTECTED] Dartmouth, Nova Scotia, Canada
Olds List Admin Info: http://oldslist.oldsgmail.com
